Method of blast-furnace smelting.



J. N ESMITH. METHOD or BLAST FURNACE SMELTING.

APPLICATION FILED OUT. 2,1907.

Patented Jan. 19, 1909.

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J. W. NESMITH. METHOD OF BLAST FURNACE SMELTING.

APPLICATION FILED OOT. 2,1907.

Patented Jan. 19, 1909.

3 SHEETSSHEET 2.

J. W. NBSMITH. METHOD OF BLAST FURNACE SMELTING.

APPLICATION FILED OUT. 2, 1907.

Patented Jan. 19, 1909.

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JOHN W. NESMITH, OF DENVER,

COLORADO, ASSIGNOR TO COLORADO IRON WORKS COMPANY, OF DENVER, COLORADO, A CORPORATION OF MAINE.

METHOD OF BLAST-FURNACE SMELTIN G.

Specification of Letters Patent.

Patented Jan. 19, 1909.

Application fil ed October 2, 1907. Serial No. 395,655.

To all whom it may concern:

Be it known that I, JOHN W. NESMITH, a citizen of the United States, residing at Denver; Colorado, have invented certain new and .5 useful Improvements in Methods of Blast- Furnace Smelting, of which the following is a specification.

My invention herein described relates to the treatment of gold, silver, copper and lead ores consisting in whole or part of copper,

or lead or iron sulfids.

The invention is an improvement in the smelting method as heretofore practiced and consists in supplying heat generated outside 5 the furnace, to the shaft thereof, preferably from crude petroleum or gas, the heat thus supplied being utilized in lieu of the solid carbonaceous fuel as coke, charcoal or their equivalents heretofore used. 'I he method includes supplying air to the furnace, independently of the heat generated outside and forced into the furnace.

An apparatus for carrying the invention into effect is illustrated in the accompanying drawing, in Which Figure 1 is a sectional view. 2 is a plan view. Fig. 3 is a modification.

I utilize a blast furnace shaft of the same general design as those in common use for pyrite smelting or copper matting, and, with some modifications, for lead smelting, and having auxiliary thereto a fire box or combustion chamber of suitable proportions for burning the necessary quantity of crude oil or petroleum, to supply an adequate equiva lent of heat to the shaft of the furnace into which the ores and fluxes for smelting are charged, to consummate the smelting continuously to completion as such ores and fluxes are charged in the heat from the crude oil or petroleum being used instead of coke, or other solid carbon fed in with the ore, as fuel only. The oil or gas fuel in this system is burned in a fire box or combustion chamher, segregated entirely as to combustion from the ores and fluxes being smelted in the blast furnace, so that the chemical reactions incident to the combustion of carbonaceous fuel for the production of heat necessary for smelting shall not take place in contact with the ores being smelted, in order to avoid the complications involved in burning carbonaceous fuel in contact with the ores and fluxes or with the air blast in a smelting o eration whose necessary reactions are wholly oxidizing, as in smelting sulfid ores to a regulus or matte product. Air is blown into such a furnace for the purpose of furnishing the oxygen necessary to oxidize the waste materials, as the sulfur and the iron of the sulfid ores, the latter to iron oxid to combine with the silica in the ore to form a fluid slag to flow freely away to the dump, the sulfur up the chimney to the atmosphere.

Oxygen has a stronger affinity for carbonaceous fuel, as coke, or charcoal or oil, than it has for iron or sulfur, and hence when such carbonaceous fuel as coke or charcoal or oil is charged into the furnace with the ores, or oil is burned in the air blast of the furnace, 7 no reaction can take place of oxygen with iron and sulfur until the carbonaceous fuel has been fully satisfied with oxygen or unless there is a surplus of oxygen going into the furnace over and above that demanded by the carbonaceous fuel. In other words, the combustion of carbonaceous fuel in the atmosphere of the blast furnace smelting to a matte product, is essentially counteractive of the oxidizing reactions involved in such 3 smelting methods, and hence the use of carbonaceous fuel burning in contact with ores being smelted, under the action of the air blast is entirely avoided in this method. The oxygen of the air blast blown into the 35 furnace is supplied thus, from the blower, purely for the purpose of oxidizing and so disposing of the iron and sulfur and other sulfids and waste materials. All carbonaceous fuel burned in the atmosphere of such furnace is robbing it of the equivalent of gxygen involved in the burning of such car- In my improved method the heat, necessary to be supplied to the smelting furnace, is produced by burning oil or gas to its ultimate products of combustion in a combustion chamber outside of the blast furnace where the ore is smelted, and the heat so produced is conveyed by convection through suitable ducts together with the inert gases of combustion, into the smelting furnace, and so the necessary heat for smelting the ores is supplied to the furnace without the counteractive effect involved where carbonaceous fuel is burned in the atmosphere of the furnace or in contact with the ores being smelted. In some cases so much coke or other hard carbon is used in the furnace stack with the ores, as is necessary to the reducing reaction from oxid to metal orother necessary reactions of such natureinvolved in such reducing. smelting, but no hard. car

bon is used in the furnace stack for producing heat, or for other purposes than that named above.

In the drawings A is a blast furnace of usual construction, having twyers B. A fire box or combustion chamber is shown at C in which petroleum or other fluid or gaseous hydrocarbon is burned for the production of heat.

His a blower of usual construction furnishing air to the chamber 0, in quantity sufficient to maintain complete combustion of the oil or gas in the fire box and under pressure sufficient to force the heat and products of combustion from the chamber into the smelting furnace. A duct or fiue D connects the furnace with the combustion chamber 0, through which the heat, with the products of combustion generated in the fire box are forced directly into the blast furnace against the pressure maintained in the blast furnace stack A by the air blast from the blower G supplying the twyers.

E is a general form of bustle pipe with an air duct F delivering the air blast from the blower G necessary to the rocess of smelting the ores in the stack. ne form of such air duct F (Fig. 3) is made as a slot or rectangular opening parallel with the plane of the furnace hearth, and preferably of such roportions as to admit the full blast of air rom the blower G without constriction, as is involved in the use of the twyers 13 shown in Fig. 1 and commonly employedat the entrance to the furnace.

air blast duct F and the heat duct D in the form.- shown, enter the furnace Apr-sf erably' in. so near proximity to each other that the heat and heated gases from the combustion chamber C :meet and commingle with the air blast within the blast furnace, thus warming or heating the air blast immediately on its entrance and avoiding the paralyzing'effect of cold air in the smelting zone, while at the same time the heat over and above that utilized for heating the air in the blast furnace A necessary for the smelting operation, is provided through the heat duct D from the combustion chamber C. In this method it is also convenient to use liquid or gaseous fuel, to which the air may be accurately supplied in such proportions as to secure perfect and complete combustion.

I claim The hereindescribed method of treating sulfid ores which consists in feeding a mixture consisting solely of ores and fluxes into a blast furnace, burning a suitable fuel ex-- terior to the furnace, and passing the hot combusted products into the blast furnace to supply the heat necessary for the reduction of the ore, and supplying air to said furnace independently of combusted products to furnish the oxygen necessary for the proper reduction of the ore.

In testimony whereof, I affix my signature in presence of two witnesses.

JOHN W. NESMITH.

Witnesses:

HENRY E. COOPER, WALTER DONALDSON. 

